Navigational aid



Dec. 11,1945.

G. s. STANTON NAVIG'ATIONAL AID Filed oct, 22, 1942 Patented Dec. 11. 1945 U N l TED STAT ES PATENT i 10F F ICE NAVIGATION-A1.

` YGeorgeSidney Stanton, Kansas City, Mo. nppneatiun october .22, 1942,seria1 10.462351 6 anims. (c1. 33;-75)

`This invention 'relates-to navigational aids, and more particularly to an instrument for laid-ing airmen in solving practical problems in navigation, especially lin dead reckoning navigation; the

principal objects of the present invention being to provide =a convenient, economical .and Y,eflieient navigational aidof the character noted.

Other objects of the invention are to provide a navigational aid in which a calibrated rule and protractor are combined as a single'ins'tru-f ment Without loss of the functions of such :devices used separately; to provide a 'scaleor 'chart associated with the instrument Vfor aiding in solving navigational problems; .and to provide Ithe ruleprotractor-.chart With indicia :having relation vto structural portions of the 'instrument and` which are operative in various positions of lthe instrument.

Other objects. ofthe invention :are tofso'a'rrange the present navigational `aid 'that `it bears a `peculiar `erelationship to 'available standard;naviga.-V

tional 'chartafthus'facilitating solution of navigaj tional problems from` a practical standpoint.

AIn accomplishing these and otherfobjects 'of the present invention, I have provided .improved details of structure. the ypreferredformfof which 4is illustratedfin the `accompanying drawing, `wherein Fig. 1 is aplan View :of my improved navigational aid.

l Fig. 2 :is a fragmentary plan view ofzmy im. Aproved .navigational aid, particularly illustrating its .relation to a practicalproblem Yand :indicating its manner of use,

Fig. `3 is a diagrammatic representation fof a doublewind drift problem, indicating the `manner in which the `present navigational aid facilitates the solution-of such problem.

Referring moren `detail to the drawing:

` I generally ydesignates `a navigationaI aid "embodying the features f of the present invention, which preferably includes `a. rule 2 and Ya protractor 3 integrally combined, and.. further, preferably arranged relative to eachother insuch-a manner thatthe l80., 180-3601diameter4of the protractor aligns with one longitudinal edge 5 ofthe rule 2. Y

The edge 5 of the rule f2 is preferably calibrated in accordance -With the scale of available standard sectional or regional charts, "for `example of Lambert Conic conformal type, wherein the scale is -ei'gh't miles to one :inch in sectional charts and sixteen Vmiles toene inch in regional charts. Italsoshasbcen found preferable to make erses a given number of meridians, a desirable number in the `Urn'ted fStatesfbeing vapproxin-iately four meridiana Navigational problems may ithus bel-solved 'on a tourmer-idian basis, as is 'csustontary,` without the necessity for shiftingthe instrument llongltudinally between -an intended poitof departure and a point A'of 'intended destination.

'-Ihefoppos'ite longitudinal edge 6 of the `rule is preferably calibrated in -a suitable .scale such as subdivisions of the metric scale :and in :this in.- stance in tenths lof centimeters,` :in Jsuc'h `a .manner as fte facilitate the :solution fo'fprob1ems ina convenientmanner von .standard size paper that is .usually available. In this Way each `calibration may designate one` mile .and a convenient rdesig: nation is thuslprovided. .ilormulae customarily yemployed in ythesolution olf navigational problems :are ialso :preferably .provided on the rule, substantially asindicated.

.Arranged .midway the length of the :edge .5 of the rule 2 iszan opening 'l to which an arrow' 8 'points f or :designating fthe center 'ofwthegplotractor 3 on the rdiameterA thereof. The diametrical line 4 ts 'also designated asa line which-represents True heading :as rdstingulshable from la True course or other navigational line. Arrangedadjacent :the rends` of the True heading line -4 are indicia R :and In respectivelyrdesignating the right and left :hand sides of the heading line relative tothe center 1 thereof. f

lt will be noted that the protractor 3 is so arranged that, .starting With the left handlside there of, the degrees read .from zero to ina unitary series V9 of angular degrees and yf-rom `1:8() 1505360 degrees in-ja `unitary 'series `Il! thereof, .andethat adjacent numbers :are reciprocals -of each other insofar :as 'directional angles are concerned.

YIt Will also be noted that Ithe R Aand L designations 4relate to eitherseries of angles when arranged on Yeither sideof a north-south line. and tha-terrors in reading angles and vcalcnlating their recipro'cals are therefore minimized.

Arranged interiorlyfof Athe protractor 3 andon the field.tl'i'ereof is fa scale, chartfor thelike generally designated H andshowing Course and Heading designations. Variations and De-g vations, `together with Wind correction angle" designationsyare also provided. All vof the noted designations =are preferably provided with ASpaces t2 adjacent thereto that are preferably provided with "a mai-t surface to provide ha lwriting'surface thereon, as indicated in dotted lines at t3, Fig! .z `Further :aids in computing 'problems fon' the scale 1H are provided inthe arrows ier :example, JM., which indicate'that -n using-the cha-rt II, Variation and deviation west are added when progressing downwardly relative to the scale or chart; that Wind correction angles are added to Course designations as indicated by the arrow, for example, I5, when the problem is progressing to the right relative to the chart II, and that Variation and deviation east are added to the scale or chart II designations when progressing upwardly relative to the chart as indicated by. the arrow, forlexample, I6.

Ground speed and Air speed are importa-nt elements in solving navigational problems and such speeds bear a relation to courses and headings respectively. Ground speed, therefore, is preferably designated GS and arranged adjacent a writing surface I1 in convenient relation to the True course (TC) co1- umn of the chart Il, whereas .Airv speed is designated AS and arranged adjacent a writing surface I8 related to the True heading (TH) 1column I2 of the chart Il.

While-the operation of my improved navigationalaid may be 4apparent to airmen and those skilled in the art of navigation, it may be helpful to describe the operation of the instrument in solving typical navigational problems preparatory to flight or encountered in night. It will berecognized that-this problem is worked on a basis of an hours duration, as is customary with problems of this type'.

Fig. 2 illustrates such a problem in which a True heading is to be computed toward which an aircraft may bedirected in order to travel a proper True course from a pointl of departure A to an intended destination B, the wind direction and velocity being knownat a point of departure fA, and,'in this instance, being illustratively indicated as forty miles per hour from thirty degrees.

As is known, wind is designated asr being from a direction, as indicated at I9, and the wi-nd tends to carry the aircraft on a reciprocal of 30 degrees, which is 210 degrees on the'protractor, a distance of forty miles per hour,.as indicated by the dotted line 20. The air speed of the aircraft is usually known or can be estimated, and in this instance may be designated as 100 miles'per hour and inserted in the space I8 therefor, as indicated at 2|, Fig. 2. Air speed is related to True heading, and for the purpose of this problem, 100 miles is measured from the point C, Fig. 2, to the point D on the True course, the operator using the tenth of a centimeter scale of the rule. The angle between AD and DC is vthe Wind correction angle and in this instance is 20 degrees.

The problem illustrated in Fig. 2 indicates that the destination"B is due west of the poi-nt of departure A, in which instance the true course to destination is 270 degrees. The true course may thus be applied to the writing surface in the chart I I on the protractor, as indicated at 22, The wind correction angle 20 degrees may be applied as indicated at 23, to the writing surface adjacent the uppermost designation W for Wind.

rThere thus remains but the problem of computing the True heading based on either addition or subtraction of the Wind correction angle from the "True course. The indicia R and-L designating right and left wind or the like, and arranged-on the protractor relative to the True heading line, may now be used to advantage for indicating whether the wind correction angle shouldl be added or subtracted to the True course designation. To effect the solution, the hole 1 in the protractor is arranged at the juncture of the True course and True heading lines, a-nd the True heading line of the instrument is placed on the True heading line of the problem, as shown in Fig. 2. Such an arrangement results in placing the Rl on the protractor within the wind correction angle to indicate that the wind is right and not left. The designation R is then addedto the Wind correction angle as indicatedrat 23, and in accordance with the formula I5 to Add wind right a True heading of 290 degrees is `computed.

It is apparent, therefore, that a forty mile wind from degrees requires a True heading of 290 degrees in order for an aircraft to travel a True course of 270 degrees from the point of departure A to its destination B.

It is believed apparent that variation caused by the fact that magnetic north does not correspond with true north and by local magnetic disturbances of the earth and deviation caused by magnetic disturbances within the aircraft itself, both relative to a magnetic compass in the aircraft, may be compensated for, as indicated on the scale or chart II, as taught by the formulae.

A further relationship of the indicia and Structural elements of the present navigational aid is illustrated in Fig. 3, wherein a double wind drift problem and its solution are illustrated.

As is well known, wind sometimes shifts at different altitudes and at different points along a course and the pilot nds it desirable to determine what changes in the wind occur throughout a trip. As indicated in Fig. 3, therefore, and using the line 24 for a True course, the pilot turns right 45 degrees on a True heading line 25 of 315 degrees for a suitable length of time based upon a problem of an hours duration, and by means of a suitable drift indicator, observes a drift of l5 degrees to the left. He then turns degrees to the left on a True heading line 26 of 225 degrees for a similar length of time, and in a manner similar to the rst observation, observes a drift of 5 degrees to the right. An observed drift to the left means that the wind is from the right and in order to compensate for the drift, the True heading must be corrected.

To Vdetermine the correct compensation' for drift, the opening I in the protractor on the True heading line between the rule andA protractor is placed at the outer end of the True heading line 25 and with the 90 mark of the protractor coinciding with the True heading line 25. As indicated by the designation L, meaning left, on the protractor, the observed drift angle is markedin degrees immediately to the left`of the 90 mark. The observed left drift angle is then drawn to the left of the True heading line 25 on the line 21. lIn this instance the proper number is l5 degrees.

The same procedure is performed on the true heading line 26 to resultv in a line 28 projected at an angle of 5 degrees right from the True heading line 26. At the intersection 28 ofthe lines 2T and 28, a line is extended to a northsouth line 3|] passing'through the juncture of the True heading lines 25 and 26, which line is designated 3l and represents wind In this instance, 'on the scale used, the wind is found to =be twelve miles per hour and from 65 degrees. i

A change in wind may thus be determined. and the .True heading. changed, if necessary, to 'com-g pensate for the difference in velocity and direction of wind relative to that determined at the point of departure.

It is apparent that the present navigational aid may be made of any suitable material, a1- though it is preferably transparent and of suflicient rigidity to withstand hard and continued usage. l

It is apparent, therefore, that the 4present invention provides a convenient, economical and eii'cient device for aiding in solving navigational problems, particularly for aircraft.

What I claim and desire to secure by Letters Patent is:

1. In a navigational aid of the character described, a combined rule and protractor, the rule being calibrated on a longitudinal edge thereof in units of eight and sixteen miles per inch, said miles per inch calibrated edge having a designation TH line thereon and a hole midway the length of said TH line, said protractor projecting laterally from said TH line uniformly with relation thereto, said protractor having a right and left indicia. on corresponding ends of said TH line.

2. In a navigational aid of the character de scribed,V a combined rule and protractor, the rule being calibrated on a longitudinal edge thereof in units of eight and sixteen miles per inch, said calibrated edge having a designation TI-I line thereon and a hole midway the length of said TH line, said protractor projecting laterally from said TH line uniformly with relation thereto, said protractor having a right and left indicia on corresponding ends of said TH line" and having numerals representing angles starting with zero and 180 degrees at the left side thereof and ending with 180 and 360 degrees at the right side thereof, said numerals being arranged as reciprocals of each other.

3. In a navigational aid of the character described, a combined rule and protractor of transparent relatively rigid material, the rule being calibrated along an edge thereof, said edge having a designation TH line thereon, said protractor projecting laterally from said TH line uniformly with relation-thereto, said protractor having a right and left indicia on corresponding sides of said TH line and having a field arranged centrally thereof and having indicia on the field representing a chart, said chart hav-' ing mat surfaces adjacent said indicia thereof adapted to receive written matter.

4. In a navigational aid of the character described, a combined rule and protractor, the rule being calibrated in centimeters along one longitudinal edge thereof and being calibrated on the opposite longitudinal edge thereof in units of eight and sixteen miles per inch, said miles per inch calibrated edge having a designation TH line thereon and a hole midway the length ofv said "TH line, said protractor projecting laterally from said TH line uniformly with relation thereto, said protractor having a right and left indicia on corresponding ends of said 'II-I line, said protractor having numerals representing angles starting with zero and 180 degrees at the left side thereof and ending with 180 and 360 degrees at the right side thereof, said numerals being arranged as reciprocals of each other, said protractor having .a field arranged centrally thereof and having indicia on the field representing a chart, said chart having Writing surfaces adjacent said indicia thereof,

and means arranged in the eld adjacent the chart for correlating the indicia of said chart.

5. In a navigational aid of the character described, a combined rule and protractor, the rule being calibrated on a longitudinal edge thereof in units of eight and sixteen miles per inch, said miles per inch calibrated edge having a designation TH line thereon and a hole midway the length of said TI-I line, said protractor projecting laterally from said TH line uniformly with relation thereto, said protractor having a right and left indicia on corresponding ends of said TH line, a eld in said protractor, and a chart in said eld having indicia and matched surfaces adjacent indicia of said chart adapted to receive written matter relating to Course and Heading designations and Variations and Deviations with Wind correction angle designations. l

6. In a navigational aid of the character described, a combined rule and protractor, the rule being calibrated on a longitudinal edge thereof in units of eight and sixteen miles per inch, said miles per inch calibrated edge having a designation TH line thereon and a hole midway the length of said TH line, said protractor projecting laterally from said TI-I line uniformly with relation thereto, said protractor having a right and left indicia on corresponding ends of said TH line, said protractor having a field arranged centrally thereof and havingl indicia on the field representing a chart. said chart havi ing Writing surfaces adjacent said indicia there- 

